1. Field of the Invention
The present invention relates to a method of manufacturing an actuator device, and to a liquid jet device.
2. Description of the Related Art
An actuator device including piezoelectric elements which make displacement when voltage is applied is mounted, for example, onto a liquid jet head and the like which ejects droplets. As such a liquid jet head, for example, an ink-jet recording head as follows has been known. With regard to the ink-jet recording head, part of each of pressure generating chambers, which communicate respectively with nozzle orifices, is composed of a vibration plate. This vibration plate is caused to be deformed by the piezoelectric elements, thus pressurizing ink in the corresponding pressure generating chamber. Thereby, ink droplets are ejected from the nozzle orifices. In addition, for the ink-jet recording head, there have been two types which are put into practical use: one being mounted with a piezoelectric actuator device of longitudinal vibration mode, which extends and contracts in the axial direction of the piezoelectric element; and the other being mounted with a piezoelectric actuator device of flexure vibration mode. For ink-jet recording heads using the actuator of flexure vibration mode, there has been an ink-jet recording head having piezoelectric elements which have been formed in the following process: for example, an even piezoelectric layer is formed on the entire surface of the vibration plate by a deposition technique. Thereafter, the piezoelectric layer is cut into pieces, each of which has a shape corresponding to each of the pressure generating chambers by use of a lithography technique. Thus, piezoelectric elements are formed in a way that the piezoelectric elements in the respective pressure generating chambers are independent of one another.
For this piezoelectric layer (piezoelectric thin film) for example, ferroelectrics such as lead-zirconate-titanate (PZT) is used. In addition, such a piezoelectric thin film is formed in the following process: for example, titanium crystals are deposited on a lower electrode by use of a sputtering method or the like. Thereafter, a piezoelectric precursor film is formed on the titanium crystals by use of a sol-gel method. Then, this piezoelectric precursor film is baked, and accordingly, the piezoelectric thin film is formed (see Patent Document 1, for example).
If the piezoelectric layer were formed in such a manner, crystals of the piezoelectric layer could be grown with titanium crystals serving as nuclei. Accordingly, columnar crystals respectively with relatively high denseness could be obtained. However, it is difficult to control the crystallinity of the piezoelectric layer, and it is not possible to homogenize electrical or mechanical characteristics of the piezoelectric layer. This brings about a problem that displacement characteristics of the respective piezoelectric elements are uneven. Incidentally, such a problem is caused not only when an actuator device which is going to be mounted onto a liquid jet head such as an ink-jet recording head and the like is manufactured, but also when an actuator device which is going to be mounted onto another apparatus is manufactured.
(Patent Document 1)
Japanese Unexamined Patent Publication No. 2001-274472, p. 5.